Paperboard containers are used to ship and store items in all types of environmental conditions. These containers are typically formed from a single layer of corrugated paperboard sandwiched between a pair of flat paperboard sheets. While this construction results in a light and rigid structure, it provides little thermal insulation and cushioning. As a result, the contents stored therein will have little protection from heat and cold as well as from rough handling. More importantly, items that must remain at elevated or lowered temperatures will quickly experience adverse temperature changes.
One method for providing insulation in corrugated containers is to use molded expanded polystyrene (EPS) blocks or containers inserted into a corrugated box as a packing material. This type of material, however, has several drawbacks. Although EPS is rigid and lightweight, it is brittle and tends to fracture with handling and use. It is also bulky and space consuming. In addition, the chlorofluorocarbons used in EPS are known to have a depleting effect on the stratospheric ozone and will not meet new government standards as to its effect on the environment.